Objective This study examined the value of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1)in serum and exhaled ventilator condensate (EVC)in early diagnosis and prognosis of ventilator-associated pneumonia (VAP). Methods A total of 37 adult patients undergoing mechanical ventilation were evaluated after treatment,including 24 patients with infection,13 without infection.Of the 24 patients with infection,10 patients were assigned to ineffective subgroup and 14 to effective subgroup.Levels of sTREM-1 in serum and EVC were measured on days 1,3,5,and 7 for all patients.sTREM-1 in serum and EVC were determined in patients by double antibody sandwich enzyme-linked immunosorbant assay (DAS-ELISA).The early diagnostic and prognostic value was assessed by receiver operating characteristic (ROC)curve analysis.Re-sults On Day 1,the sTREM-1 levels in serum and EVC did not show significant difference between the three groups (P>0.05).On Day 3 and Day 5,the level of sTREM-1 in the infection group was higher than that in the non-infection group (P <0.01).On Day 7,the sTREM-1 levels of serum and EVC in ineffective subgroup were higher than those in the effective subgroup and non-infection group (P <0.01). There were no difference between the non-infection group and effective subgroup (P >0.05).For ROC analysis,area under the curve (AUC)of serum sTREM-1 was 0.897,and AUC of EVC sTREM-1 was 0.909 on Day 3.When the cut-off value of EVC sTREM-1 was set at 4.70 ng/mL on Day 3,the sensitivity was 85.8%,specificity was 92.3%.Conclusions The results suggest that the levels of sTREM-1 in serum and EVC are conducive to the early diagnosis of VAP.The levels of sTREM-1 in serum and EVC on Day 7 are helpful for estimating the prognosis.EVC sample is easier to collect than serum.

Objective To explore the extensively drug resistant mechanism and clinical treatment strategy of Klebsiella pneu-moniae .Methods The isolate was identified by Vitek2 Compact System.Antimicrobial susceptibility testing was conducted by Kirby-Bauer method.KPC-2 carbapenemase was detected by modified Hodge test.The gene encoding KPC-2 carbapenemase was amplified by polymerase chain reaction (PCR)and then sequenced.Results The strain was resistant to all antibiotics used in routine antimicrobial susceptibility testing except amikacin.Modified Hodge test showed positive result.KPC-2 gene was detected by PCR.The sequence was consistent with that of 11844849 in GenBank.After treatment for one month,no exten-sively drug resistant K.pneumoniae strain was detected from the patient.Conclusions It is necessary to strengthen the monito-ring and improve the awareness of extensively drug resistant K.pneumoniae for better control of such infections.

Objective To summarize the characteristics of nosocomial infections in the patients treated in intensive care unit (ICU).Methods The incidence of nosocomial infections was monitored in ICU from March 2012 to August 2012.The incidence rate of infection was adjusted with Average Severity of Illness Score (ASIS)score and analyzed in relation to three invasive pro-cedures.Pathogen distribution of nosocomial infections in ICU was also analyzed.Results Nosocomial infection was identified in 357 of the 3 700 ICU patients (9.65%).The overall daily infection rate was 30.34‰,specifically,49.10‰ for ventilator asso-ciated pneumonia (VAP),13.86‰ for catheter-related bloodstream infections (CRBSI),and 1.09‰ for catheter-associated urinary tract infections (CAUTI).Of the 688 bacterial isolates,gram negative bacteria accounted for 82.70%.The top three bacterial species were Acinetobacter baumanii ,Pseudomonas aeruginosa ,and Klebsiella pneumoniae .Conclusions ICU is the focus for surveillance of nosocomial infections.Objective investigation is critical for nosocomial infection surveillance.

Objective To study the drug resistance mechanism and homologous relationship of four clinical strains of carbapen-em-resistant Klebsiella pneumoniae isolated from different sites of the same one patient.Methods Four carbapenem-resistant K .pneumoniae strains were isolated from blood,urine,sputum and pelvic drainage of a patient after cystectomy in clinical mi-crobiology lab of Xinhua Hospital in March 2012.① Modified Hodge test was used to detect the expression of carbapenemase.② PCR amplification assay and DNA sequencing were used to detect resistance-related genes.③ SDS-PAGE analysis was per-formed to analyze outer membrane porin components of the four carbapenem-resistant K .pneumoniae isolates.ERIC-PCR as-say was used to analyze the homology of these carbapenem-resistant isolates.Results Modified Hodge test demonstrated that all the four carbapenem-resistant K.pneumoniae expressed carbapenemase.KPC-2 gene was identified in all the four isolates by PCR test and DNA sequencing.SDS-PAGE analysis indicated an outer membrane porin alteration common to all the four iso-lates which is distinct from that of the strain sensitive to antibiotics.The identical DNA fingerprinting of the four strains was confirmed by ERIC-PCR analysis.Conclusions The antibiotic resistance mechanism of the four carbapenem resistant K.pneu-moniae associated with this case includes the expression of KPC-2 and altered outer membrane permeability induced by abnormal expression of outer membrane porin.These four strains belong to one common clonal group.

Objective To investigate the prevalence and the transmission of oqxAB gene in clinical strains of Escherichia coli and Klebsiella pneumoniae .Methods Nonduplicate clinical isolates of E.coli (n=72)and K .pneumoniae (n=49)were col-lected.The oqxAB gene was amplified by PCR.The product was sequenced.Plasmid conjugation experiments were done in oqxAB-positive E.coli and K.pneumoniae strains to detemine whether oqxAB gene is located in plasmid.The MICs and mu-tant prevention concentrations (MPCs)for ciprofloxacin were determined in transconjugants with oqxAB gene by agar dilution method.Results The oqxA,oqxB and oqxAB were identified in 15,4,and 7 of the 72 strains of Escherichia coli and 4,1,and 34 of the 49 strains of K.pneumoniae,respectively.The oqxAB gene was positive in 2 (2/16)ciprofloxacin sensitive and 5 (5/56)ciprofloxacin resistant E.coli strains,in 8 (8/14)ciprofloxacin sensitive and 26 (26/35)ciprofloxacin resistant K. pneumoniae strains,respectively.The E.coli and K.pneumoniae strains with or without oqxAB did not show different sus-ceptibility to ciprofloxacin.The oqxA and oqxB sequences from E.coli and K.pneumoniae showed 99% similarity to the se-quences of GeneBank accession number AB601773.1 and accession number FJ975561.1,respectively.The oqxAB gene was successfully transferred in 4 of the 5 oqxAB-positive E.coli strains.The MIC of ciprofloxacin was 0.25-0.5 mg/L against the transconjugants,31-62 times higher than the MICs for the recipient strains.The MPC of ciprofloxacin was 8-16 mg/L against the transconjugants,32 times higher than that for recipient strain J53.The oqxAB gene were not transferred in K. pneumoniae. When the MIC of ciprofloxacin was ≤0.062 5 mg/L,the MPC of ciprofloxacin was 0.25-0.5 mg/L for K.pneumoniae strains with or without oqxAB.When MIC was 0.25-0.5 mg/L,the MPC of ciprofloxacin was 2-16 mg/L for K .pneumoniae strains with or without oqxAB .Conclusions oqxAB gene is present in E .coli and K .pneumoni-ae .The oqxAB gene spreads through plasmid in E .coli.The nonsiginificant difference of oqxAB prevalence between ciproflox-acin sensitive and ciprofloxacin resistant strains indicates that oqxAB gene may mediate low level resistance to ciprofloxacin in E.coli.The E.coli transconjugants of oqxAB gene can produce high level resistance under the selection pressure of ciproflox-acin.The high level resistance in K .pneumoniae under selection pressure of ciprofloxacin is not associated with oqxAB gene, but related to the ciprofloxacin MIC against these strains.

Objective To investigate the bacterial resistance of clinical isolates collected in Tongling area during 2011.Methods Antimicrobial susceptibility testing was conducted by Kirby-Bauer method.All the data were analyzed by WHONET 5.5 soft-ware.Results A total of 2 690 clinical isolates were collected during 2011,of which gram negative organisms and gram positive organisms accounted for 74.2% and 25.8%,respectively.MRSA and MRCNS accounted for 45.1% of S.aureus and 71.6%of coagulase negative Staphylococcus,respectively.MRSA and MRCNS showed higher resistance to gentamicin,ciprofloxacin and erythromycin than the corresponding methicillin-susceptible strains.No vancomycin- or teicoplanin-resistant strain of Staphylococcus spp.was identified.The resistance rate to penicillin,nitrofurantoin and fosfomycin was low in E.faecalis.No ampicillin-,vancomycin-or teicoplanin-resistant strains were found.For E.faecium,some strains were resistant to vancomy-cin and teicoplanin.About 46.6% of E.coli isolates and 27.7% of Klebsiella isolates produced extended-spectrumβ-lactamas-es (ESBLs).No imipenem-or meropenem-resistant isolate was found.The percentage of P .aeruginosa strains resistant to imipenem,meropenem and amikacin were 29.5%,36.9%and 2.3%, respectively. More than 60.0% of the Acinetobacter strains were resistant to all the antibiotics test-ed except minocycline and cefoperazone-sulbactam,to which 26.4% and 12.5% of the strains were resistant.Conclusions No glycopeptides-resistant isolate was found in gram positive organisms except E.faecium.The resistance rate of Enter-obacteriaceae isolates was lower to imipenem,meropenem, cefoperazone-sulbactam,piperacillin-tazobactam and amika-cin.The prevalence of resistant strains is still increasing,es-pecially carbapenem-resistant P .aeruginosa and carbapenem-resistant A.baumannii.It is mandatory to take effective antibiot-ic policy and infection control measures.

Objective To determine the genetic subtypes and susceptible population of Cryptoccocus neoformans in China. Methods We analyzed 129 strains of Cryptococcus neoformans isolated during the period from 1980 through 2006 in 18 Prov-inces and municipalities of central and eastern China using epidemiological method,PCR fingerprint,and multilocus sequence typing (MLST).Results About 71.5% (91/129)of the clinical strains were isolated from the patients without any recognizable immunodeficiency.Only 8.5% (11/129)of the strains were from AIDS patients.The remaining 20.9% (27/129)were from patients with underlying diseases other than HIV infection.Furthermore,PCR fingerprinting and MLST showed that serotype A strains exhibited a unique VNⅠsubtype,which was distinguishable from the reference VNⅠmolecular types.For convenience we named this unique genotype as VNⅠc.Conclusions People without any recognizable immunodeficiency are the main susceptible population of the 129 clinical strains of Cryptococcus neoformans ,which contrasts with the reports from other countries.The different genetic subtypes of Cryptococcus neoformans between China and other countries may contribute to such a difference.

Objective To investigate the antimicrobial resistance of Haemophilus influenzae in Peking Union Medical College Hospital for rational clinical treatment.Methods A total of 223 strains of H .influenzae were collected from patients from Jan-uary 2008 to December 2011.The antimicrobial susceptibility was tested by Kirby-Bauer method.Production of beta-lactamase was detected using nitrocefin disks.WHONET 5.6 software was used to analyze the data of susceptibility testing.Results Tri-methoprim-sulfamethoxazole and tetracycline were the two antimicrobial agents to which the H .influenzae strains were most resistant.Theβ-lactamase positive ampicillin resistant strains accounted for 15.9 %,andβ-lactamase negative ampicillin resist-ant strains accounted for 8.9%.Conclusions H .influenzae is mainly isolated from respiratory specimens.Majority of the anti-microbial agents still show good antibacterial activity against H .influenzae strains.However,H .influenzae isolates are highly resistant to trimethoprim-sulfamethoxazole and tetracycline.

Objective To characterize the growth curve of Brucella in Bact/Alert blood culture system which may be helpful to predict the growth of Brucella strain for earlier clinical diagnosis of brucellosis.Methods The epidemiological,clinical and labo-ratory data including growth curve of Brucella were reviewed and analyzed retrospectively for 15 cases of brucellosis as con-firmed by positive serological test and brucellosis agglutination test.Results All the 15 patients had irregular fever and history of animal exposure,even though their clinical feature and signs varied greatly.The growth curve of Brucella in blood culture showed the same chracteristics in the 15 patients,including:the time to positive alarm was about 72 hours,a longer lag phase, shorter logarithmic phase,a shorter vertical axis corresponding to the logarithmic phase,and a flat stable phase.Conclusions The clinical manifestation of brucellosis is variable and non-specific.Lack of awareness of this disease makes the clinicians mis-diagnose it easily.Therefore,blood culture is critical for clarifying the etiology in febrile patients.The growth curve of bacteria during blood culture is useful for early diagnosis of brucellosis and prevention of laboratory infections.

Objective To study the prevalence and sequence homology of virulence genes exoU and exoS in 53 strains of pan-drug-resistant Pseudomonas aeruginosa .Methods The virulence genes exoU and exoS were detected by PCR.Sequence homo-logy was analyzed by BOX-PCR.Results Of the 53 clinical isolates of pandrug-resistant Pseudomonas aeruginosa ,the exoS+/exoU- genotype was identified in 40 strains,exoU+/exoS - genotype in 10 strains,exoS +/exoU+ genotype in 1 strain, and exoS-/exoU- genotype in 2 strains.BOX-PCR results showed that 41 exoS+ isolates belonged to 24 genotypes,and 11 exoU+ strains could be grouped into 7 genotypes.Conclusions The prevalence of virulence genes is high in clinical isolates of pandrug-resistant Pseudomonas aeruginosa .BOX-PCR fingerprint analysis combined with sequence homology analysis is help-ful for effective monitoring and control of hospital pandrug-resistant pseudomonas aeruginosa infection.